VerticalResponse, a provider of Web-based self-service marketing tools for small businesses, has acquired social network marketing technology company Roost, the companies announced today. Financial terms of the deal were not disclosed. Both companies are based in San Francisco, which helped the two "get to know each other" and realize they had similar audiences, Roost said in an announcement to users.Roost was founded in 2007 as a property search portal. In September 2010, the company changed its business model to focus on helping real estate agents and brokers gain referral business through social networking on Facebook.In late March 2011, Roost unveiled its social marketing platform and simultaneously expanded its business model beyond real estate professionals to other sma...